I'm looking to upgrade my old fluorescent lighting on some of my tank racks. For a setup with four 10 gallon verticals on one rack shelf should I use a single T5 HO Bulb Fixture or a duel bulb unit? A 48 inch 54 watt HO Bulb puts out between 4700 and 5000 Lumens. I have creeping fig and bromeliads in these tanks.